How Long Are Leftover Mashed Potatoes Good For? + Tips

Learn how long leftover mashed potatoes are good for, along with storage and reheating tips for best taste and safety. 

To cut to the chase–leftover mashed potatoes generally last for up to 4 days when kept cold continuously.

Creamy, buttery, and often the star of the show, mashed potatoes are beloved in many households. But what happens when the meal ends and a generous portion of these tasty spuds remains untouched?

…how long are leftover mashed potatoes good for and how long can you store them before they are too old to eat?

Knowing how long leftover mashed potatoes last can prevent food waste, keep meals delicious, and, most importantly, avoid potential health hazards associated with eating mashed potatoes that haven’t been stored correctly.

In this FAQ, we’ve got some guidelines for storing leftover mashed potatoes for best taste and texture.

Why Mashed Potato Storage Matters

Anyone who has made mashed potatoes for a crowd knows that measuring how much to make is an imperfect science. They go great with holiday meal leftovers, naturally, but even if you’re whipping up Hungry Man mashed potatoes from a box, why waste them?

Mashed potato storage matters for several compelling reasons:

• Minimizing food waste. Proper storage prevents mashed potatoes from going to waste, saving food and money.
• Convenience. Storing mashed potatoes in advance is a time-saver for busy schedules and meal preparation.
• Health and safety. Effective storage prevents spoilage and foodborne illnesses, ensuring your well-being.
• Quality preservation. Proper storage maintains mashed potato texture and flavor over time.
• Versatility. Stored mashed potatoes can be used as a base for various dishes, including loaded mashed potato casserole, potato soup, potato pancakes, and shepherd’s pie.

How Long Are Leftover Mashed Potatoes Good For?

As per USDA, any cooked potatoes, including mashed potatoes, can be kept in the refrigerator for 3 to 4 days. This time frame is your golden window for enjoying mashed potatoes with no concerns about spoilage.

To ensure their quality and safety, place your leftover mashed potatoes in an airtight container. The goal here is to prevent moisture loss and avoid absorbing odors from other foods in the refrigerator.

But what if you find yourself with a mountain of mashed potatoes you can’t possibly finish within that timeframe? Don’t worry! 

Mashed potatoes can also be frozen. When kept in an airtight container or freezer bag, they can retain their quality for about 1 to 2 months, according to the Wyoming Department of Health. Just be sure to label the container with the date of freezing to know when they were frozen. And it’s best not to refreeze mashed potatoes.

Though freezing can extend the life of your leftover mashed potatoes, I don’t recommend this method as it can change their texture and consistency, often resulting in less desirable quality when they’re thawed and reheated. 

Therefore, if you have the choice, it’s often better to enjoy mashed potatoes fresh or use alternative storage methods like refrigeration for shorter periods.

How Long Do Instant Mashed Potatoes Last?

Prepared instant mashed potatoes typically remain good to eat for up to 5 days when refrigerated. Take note that instant and homemade mashed potatoes, when prepared and stored properly, should last for a similar time frame in the fridge. Stir well as you heat and serve since they can become watery.

It may take a long time for manufactured mashed potatoes to get moldy. They might not be good to eat, even if you don’t see mold. If they smell bad, look gray, or it’s been over a week in fridge, don’t risk it and just throw them out. 

The preservation of both depends largely on the added ingredients (like butter, milk, cream, etc.) and how they’re stored. To keep prepared instant mashed potatoes fresh, put the leftovers in a sealed container or wrap them in plastic before putting them in the fridge.

Just so you know: Most instant (dry) mashed potatoeshave a best-before and best-by date on their packaging and generally last for 6 months to a year past this date. The Idahoan brand doesn’t recommend using their product past the best-by date as the potatoes will start to break down, affecting the taste, texture, and overall quality of the product.

How Long Can You Keep Mashed Potatoes Out Of The Fridge?

It’s crucial to understand that mashed potatoes should not be left at room temperature for extended periods. Bacteria can multiply rapidly at temperatures between 40°F and 140°F , putting your leftovers at risk. 

As a general rule of thumb, don’t leave any perishables, including mashed potatoes, unrefrigerated for over 2 hours. If the ambient temperature rises significantly, say above 90°F, this window narrows to just 1 hour.

Leaving mashed potatoes out overnight is a big no-no. They can become a breeding ground for harmful bacteria and foodborne illnesses. So, always err on the side of caution and discard any mashed potatoes that have been sitting out for too long.

How Long Do Mashed Potatoes Last In The Refrigerator?

• Homemade mashed potatoes, when kept cold, can last up to three days.
• Instant mashed potatoes, because they often have preservatives, can last up to five days.

Like we discussed earlier, you can store your leftover mashed potatoes safely in the refrigerator for 3 to 5 days. Beyond this point, their quality and safety start to degrade. So, if you foresee having mashed potatoes you won’t consume within this timeframe, freezing is your best bet to avoid food waste.

Is It Safe To Eat Mashed Potatoes Left Out Overnight?

In a word, NO. It isn’t safe to consume mashed potatoes that have been left out overnight. Any food left at room temperature for an extended period is at risk of bacterial growth and spoilage. 

To avoid the potential health risks associated with consuming mashed potatoes that have been left unrefrigerated for too long, always play it safe and discard them if they’ve been sitting out overnight.

Note: Remember to use clean utensils for serving each time, and to put the container right back in the fridge. Don’t reheat mashed potatoes more than once, and don’t refreeze thawed mashed potatoes.

Signs That Mashed Potatoes Have Gone Bad

Now that we’ve established the importance of proper storage, it’s equally crucial to be able to identify when mashed potatoes have gone bad. Here are some telltale signs that your beloved mashed potatoes have taken a turn for the worse:

1. Unpleasant smell. Spoiled mashed potatoes may emit a sour, off, or rancid odor that is immediately noticeable.
2. Color changes. Keep an eye out for any significant changes in color. Mashed potatoes that have turned gray or green should be discarded.
3. Texture alterations. A noticeable difference in texture, such as becoming grainy, slimy, or overly watery, is a red flag.

Consuming spoiled mashed potatoes can lead to gastrointestinal discomfort and food poisoning. It’s crucial to recognize these signs and exercise caution when assessing the quality of your leftovers.

Tips For Storing Leftover Mashed Potatoes

Proper storage techniques are essential for preserving the quality and safety of your mashed potatoes. Here’s a detailed breakdown of the steps to take:

• Use airtight containers. Invest in a set of airtight containers that are just the right size for your leftover mashed potatoes. These containers prevent moisture loss and keep your mashed potatoes fresh.
• Label and date. Always label your containers with the date they were prepared. This helps you easily monitor how long they’ve been stored.
• Optimal placement. Store your mashed potatoes in the coldest part of the refrigerator. The back of the fridge is usually the coldest, which helps maintain their quality.
• Prevent freezer burn. Like we already explained, if you plan to freeze your mashed potatoes, ensure that your containers are airtight, but leave a little space at the top to allow for expansion during freezing.

Tips For Reheating Leftover Mashed Potatoes

Reheating mashed potatoes may seem straightforward, but there are nuances to achieving that creamy texture once again. Here are some detailed tips:

• Microwave method. Reheat in short intervals in the microwave, stirring in between to distribute heat evenly. You may need to add a splash of milk or cream to restore moisture.
• Stovetop method. For larger quantities, reheat on the stovetop over low heat. Again, consider adding a bit of milk or cream to maintain creaminess.
• Oven Method. To maintain the crispy top layer, reheat mashed potatoes in the oven at 350°F for about 20 to 30 minutes, covered with foil.

Avoid boiling. Never reheat mashed potatoes by boiling them, as this can make them watery and less appealing. For more detailed instructions, check out our How To Reheat Mashed Potatoes guide.

The bottom line

In managing leftovers, understanding their shelf life is crucial. Knowing how long leftover mashed potatoes are good for and the signs that they’ve gone bad can save you from stomachaches and wasted food. 

So, always store your leftover mashed potatoes properly, reheat them with care, and remember that when in doubt, it’s better to be safe than sorry. With these tips in mind, you can savor your delicious mashed potatoes with no food safety worries.

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